This invention relates to a vehicle door lock assembly and more particularly to such an assembly provided with sound abating means.
In the prior art, there has been developed a type of door lock assembly for vehicles which generally includes a bolt mounted on the rear side wall of the door opening of the vehicle, a rotary latch mounted on a side wall of the door which is operatively engageable with the bolt for holding the door in the closed position, and a pawl also mounted on the door sidewall which is operatively engageable with the latch for retaining the latch in the closed position. Normally, such lock components are formed of a metal having sufficient strength properties to withstand impact loads applied in the direction of travel of the door and also in a direction perpendicular to the direction of door travel.
Because of the noise resulting from the striking lock components during opening and closing of the door, it has become a common practice in the industry to coat the latch member of such an assembly with a noise absorbing or deadening material such as plastic. It has been found, however, that in order to maintain the strength properties of the components for safety purposes, coating materials of greater strength but lesser sound absorbing properties must be used which is undesirable from a noise abatement point of view. It also has been the practice of some vehicle manufacturers to provide the bolt member of such assemblies with a noise absorbing material, usually a plastic, to further deaden the noise resulting from the components striking each other. Such provision also has been found not to be satisfactory in performance in that after a period of service, the coating material on the bolt member wears or spalls.
It thus has been found to be desirable to provide a lock assembly of the type described which not only has optimum sound abating characteristics but also optimum strength properties sufficient to withstand impact loads applied to the vehicle, particularly during collision, both transversely and longitudinally.